I just got my self a 01 f-350 crew cab 4x4 with a 4 inch lift 35 inch bfg all terrains, 4.10 gears and 210k on the clock engine is bone stock. After picking it up I made an 1100 mile trek home with it.The engine seems solid with minimal blowby and seems to run like a top. Coming home the truck seemed more sluggish in the power department than I thought it should (even with 35's on it) and I could not get better than 11.9 mpg( going by mile markers on the interstate) by the odometer the mpg calculated to be 10.2. This all seems low even with the big tires. I have owned several cummins powered trucks but this is my first powerstroke. So my question is does the mpg sound low to you ford veterans? And if so could you point me in the right direction for getting the power and mpg right? I would have thought I should get at least 13 or 14 mpg with it???

Not towing. I went from phoenix AZ to East Texas. So some flat, some big hills and some little hills and it was about 65 degrees for the whole trip. No notable wind during the trip. Im sure I was on winter fuel because we went to winter blend fuel here in east texas about 3 weeks ago. Also I cant make the truck blow any black smoke at all ever... If that means anything to you??? The engine has very little blowby with no fuel leaks or oil leaks that I have found....YET!

I just purchased a 1999 f-250 CC PSD 4x4 short box in Jackson, MS. last week and drove it to Western NY. It has 33 inch tires and .373 gears. It is my second 7.3 and I put a Superchips Flashpaq 1805 tuner on the first truck and liked it so I picked up another one for this truck. I programed the speedo for the 33 inch tires and installed the Performance Tune before leaving Jackson. On my first two tanks of fuel, I got 15 MPG with the speedo running about 1 mph higher than my GPS. I ran with the cruise set at 72 MPH which put the RPMs at just under 2000. When I fueled the third time, I changed the tune to Performance Tow, ran the same speed, and the mileage went to 17.3 on that tank.

I don't know if this helps, but keeping the tach under 2000 really makes a difference.

Mine seems like a dog though. At 70 its running about 2200 with the big tires and 4.10 gears. The truck fells like im pulling a 10,000 lbs trailer all the time and the mpg matches the way it feels. I have never had a powerstroke or a pickup with 35 inch tires. IDK????

To update with the truck tcase actually in 2wd, checked my ebps, up pipes, fixed a small boost leak, and with my Garmin for a accurate speedo and odo I am getting 13.4 in town and 13.5 highway at 70ish. I just ordered a PHP phoenix to help with the SLOWNESS and maybe it will help the mpg as well. As far as tunes I got stock, 1,100 rpm high idle, 40hp heavy tow, 80hp dd, 100hp performance, and 140hp extreme. Jacob at php told me conservative driving on the 140hp tune should yield me the best economy. We shall see!

To further update in my quest for improved fuel economy I have done bellowed up pipes since I found mine were leaking horribly, pulled the intercooler tubes and boots, cleaned and inspected them, reinstalled using the hairspray trick and did the ccv mod to keep the oil from coming back. I have also removed the lift and put 6 new stock tires on. I'm looking forward to seeing if all that work yields any gains!!!

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